From d04697aee8fff61578cf3480506f13a4747892d3 Mon Sep 17 00:00:00 2001
From: mib <mib@kanp.ai>
Date: Sun, 11 Aug 2024 19:06:54 +0200
Subject: [PATCH 1/2] lib.meta.licensesSpdx: mapping from SPDX ID to licenses

---
 lib/meta.nix | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/lib/meta.nix b/lib/meta.nix
index 65d7bf99191a93a..ddd062f38c47afb 100644
--- a/lib/meta.nix
+++ b/lib/meta.nix
@@ -286,6 +286,32 @@ rec {
     ((!pkg?meta.platforms) || any (platformMatch platform) pkg.meta.platforms) &&
     all (elem: !platformMatch platform elem) (pkg.meta.badPlatforms or []);
 
+  /**
+    Mapping of SPDX ID to the attributes in lib.licenses.
+
+    For SPDX IDs, see https://spdx.org/licenses
+
+    # Examples
+    :::{.example}
+    ## `lib.meta.licensesSpdx` usage example
+
+    ```nix
+    lib.licensesSpdx.MIT == lib.licenses.mit
+    => true
+    lib.licensesSpdx."MY LICENSE"
+    => error: attribute 'MY LICENSE' missing
+    ```
+
+    :::
+  */
+  licensesSpdx =
+    lib.attrsets.mapAttrs'
+    (_key: license: {
+      name = license.spdxId;
+      value = license;
+    })
+    (lib.attrsets.filterAttrs (_key: license: license ? spdxId) lib.licenses);
+
   /**
     Get the corresponding attribute in lib.licenses from the SPDX ID
     or warn and fallback to `{ shortName = <license string>; }`.
@@ -361,10 +387,12 @@ rec {
   */
   getLicenseFromSpdxIdOr =
     let
-      spdxLicenses = lib.mapAttrs (id: ls: assert lib.length ls == 1; builtins.head ls)
-        (lib.groupBy (l: lib.toLower l.spdxId) (lib.filter (l: l ? spdxId) (lib.attrValues lib.licenses)));
+      lowercaseLicenses = lib.mapAttrs' (name: value: {
+        name = lib.toLower name;
+        inherit value;
+      }) licensesSpdx;
     in licstr: default:
-      spdxLicenses.${ lib.toLower licstr } or default;
+      lowercaseLicenses.${ lib.toLower licstr } or default;
 
   /**
     Get the path to the main program of a package based on meta.mainProgram

From f55a4b99ef73df3b17ae5e951198949a880cf3ab Mon Sep 17 00:00:00 2001
From: Silvan Mosberger <contact@infinisil.com>
Date: Sun, 25 Aug 2024 00:57:44 +0200
Subject: [PATCH 2/2] lib.meta: Minor SPDX license function improvements

- Expose `lib.licensesSpdx`
- Create bindings for the needed internal functions
- Mention that some SPDX licenses might be missing (in the future I hope
  we can autogenerate the Nixpkgs license list from some SPDX endpoint
---
 lib/default.nix |  3 ++-
 lib/meta.nix    | 14 +++++++++-----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/lib/default.nix b/lib/default.nix
index 63a31101eee7f08..0ff3a39807450aa 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -123,7 +123,8 @@ let
     inherit (self.derivations) lazyDerivation optionalDrvAttr;
     inherit (self.meta) addMetaAttrs dontDistribute setName updateName
       appendToName mapDerivationAttrset setPrio lowPrio lowPrioSet hiPrio
-      hiPrioSet getLicenseFromSpdxId getLicenseFromSpdxIdOr getExe getExe';
+      hiPrioSet licensesSpdx getLicenseFromSpdxId getLicenseFromSpdxIdOr
+      getExe getExe';
     inherit (self.filesystem) pathType pathIsDirectory pathIsRegularFile
       packagesFromDirectoryRecursive;
     inherit (self.sources) cleanSourceFilter
diff --git a/lib/meta.nix b/lib/meta.nix
index ddd062f38c47afb..57f3a46d0698ed4 100644
--- a/lib/meta.nix
+++ b/lib/meta.nix
@@ -7,6 +7,7 @@
 
 let
   inherit (lib) matchAttrs any all isDerivation getBin assertMsg;
+  inherit (lib.attrsets) mapAttrs' filterAttrs;
   inherit (builtins) isString match typeOf;
 
 in
@@ -289,7 +290,8 @@ rec {
   /**
     Mapping of SPDX ID to the attributes in lib.licenses.
 
-    For SPDX IDs, see https://spdx.org/licenses
+    For SPDX IDs, see https://spdx.org/licenses.
+    Note that some SPDX licenses might be missing.
 
     # Examples
     :::{.example}
@@ -305,18 +307,19 @@ rec {
     :::
   */
   licensesSpdx =
-    lib.attrsets.mapAttrs'
+    mapAttrs'
     (_key: license: {
       name = license.spdxId;
       value = license;
     })
-    (lib.attrsets.filterAttrs (_key: license: license ? spdxId) lib.licenses);
+    (filterAttrs (_key: license: license ? spdxId) lib.licenses);
 
   /**
     Get the corresponding attribute in lib.licenses from the SPDX ID
     or warn and fallback to `{ shortName = <license string>; }`.
 
-    For SPDX IDs, see https://spdx.org/licenses
+    For SPDX IDs, see https://spdx.org/licenses.
+    Note that some SPDX licenses might be missing.
 
     # Type
 
@@ -351,7 +354,8 @@ rec {
     Get the corresponding attribute in lib.licenses from the SPDX ID
     or fallback to the given default value.
 
-    For SPDX IDs, see https://spdx.org/licenses
+    For SPDX IDs, see https://spdx.org/licenses.
+    Note that some SPDX licenses might be missing.
 
     # Inputs